It´s like the man that takes his car to the mechanic because it´s making a bothering noise under the engine.
The mechanic asks the man to start the engine to hear the bothering noise.
After a few seconds, the mechanic takes a hammer, goes under the engine and a hard metalic blow is heard.
Try again says the mechanic. The man starts the engine and the bothering noise is gone. The mechanic says now, go for a short ride and come back to be sure that the bothering noise is gone.
The man rides his car and after a few minutes he is back, with a shiny smile and asks : How much for this ?
The mechanic says 100 bucks.
Ehhhh, 100 bucks for a hammer kick ? My son could have given that blow !
Ok, says the mechanic now : $ 1 for the hammer blow and $99 for knowing where and how to hammer.